Hello all, I have an 06 Wrangler X 4.0 auto. 72K miles

It purrs like a kitten when it's cold. As soon as it warms up ( think it's when it goes into closed loop ) it kinda stalls & starts running like crap & starts rattling & banging.

I've replaced all the sensors,

Does that include the upstream O2 sensors? An engine that runs fine when cold but starts running poorly once it starts to warm up is pretty much a sure sign that one of the two upstream O2 sensors has gone bad. The computer only looks at the O2 sensors to control the air fuel ratio once the engine has started to warm up, it uses firmware to set the air fuel ratio when the engine is cold.

If you replace the upstream O2 sensors make sure to ONLY use NTK or NGK O2 sensors, Bosch O2 sensors don't work well for long in our Jeep engines.

 

Mine does the same thing I think. Mainly just on the start ups after it has been running for a while. The advice I got on here was to replace my fuel pump, as some valve on it gets worn out or something. I have a new pump, but my jeep has been running fine lately so I haven't bothered on changing it out yet.

Long road trips or multiple errands stops seem to be the worse. Cold starts perfect everytime.

edit: I did change out all four of my o2 sensors with NTK ones and that seemed to help out a lot. All my o2 sensors were looking rough too.

 

It goes closed look in under a pin Ute if you doubt this hook up an individual port monitor and watch how fast it goes closed loop

Emission rules on newer years required closed loop long before temp gauge shows warmed up

If the coolant temp sensor or its wiring bad it can act like that
Just be aware that sensor is too close to engine fan to carelessly mess with it while engine is running


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My '98 did that last fall. No codes thrown. It would run great for about 1 to 2 minutes, then run terrible and almost cut off for a few minutes until it actually warmed up, then it would run "better". It was a bad coolant temp sensor.